Effect of composition of La0.8Sr0.2MnO3-Y2O 3-stabilized ZrO2 cathodes. Correlating three-dimensional microstructure and polarization resistance

James R. Wilson, J. Scott Cronin, Anh T. Duong, Sherri Rukes, Hsun Yi Chen, Katsuyo Thornton, Daniel R. Mumm, Scott Barnett*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

136 Scopus citations

Abstract

Composite La0.8Sr0.2MnO3 (LSM)-Y2O3-stabilized ZrO2 (YSZ) cathodes with compositions ranging from 30:70 to 70:30 wt.% LSM:YSZ were studied both electrochemically and microstructurally. Polarization resistance was lowest for the 50 wt.% YSZ composition, and increased symmetrically as the composition deviated from this value. Serial-sectioning using focused ion beam-scanning electron microscopy was implemented to reconstruct the three-dimensional cathode microstructure. Various averaged structural parameters were determined versus composition, including phase volume fractions, surface area densities, total triple-phase boundary (TPB) densities, interfacial curvatures, phase tortuosities, and the levels of phase connectivity. Typically >90% of the pore and YSZ networks were found to be intra-connected to the surrounding phase, but the LSM networks showed lower connected fractions, as low as 37.5% for a LSM weight fraction of 30%. The composition dependences of the total TPB density and electrochemically-active TPB density (i.e., TPB's on three fully intra-connected phases) were shown to agree reasonably well with simple "sphere-packing" structural models. An electrochemical model that accounted for the linear-specific resistance of TPB's, phase intra-connectivity, and oxygen ion transport in the YSZ as influenced by its tortuosity, was found to provide reasonable agreement with the measured polarization resistance versus composition.

Original languageEnglish (US)
Pages (from-to)1829-1840
Number of pages12
JournalJournal of Power Sources
Volume195
Issue number7
DOIs
StatePublished - Apr 2 2010

Keywords

  • Cathodes
  • Focused ion beam (FIB) tomography
  • Solid oxide fuel cells
  • Three-dimensional (3D) microstructure

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Physical and Theoretical Chemistry
  • Electrical and Electronic Engineering

Fingerprint

Dive into the research topics of 'Effect of composition of La<sub>0.8</sub>Sr<sub>0.2</sub>MnO<sub>3</sub>-Y<sub>2</sub>O <sub>3</sub>-stabilized ZrO<sub>2</sub> cathodes. Correlating three-dimensional microstructure and polarization resistance'. Together they form a unique fingerprint.

Cite this